[DataGrid] Fix column selector crash when hiding columns

[DanailH]

Fixes #856

[oliviertassinari]

I had a look at the logic, a couple of thought:

• The name of isEqual is confusing. It's a deep equal, isDeepEqual would be clearer.
• I have tried to remove the if (renderNewColState || newRenderedColState == null) { branch, and couldn't notice any perf rendering different. The updateRenderedCols method was returning the same order of true/false sequences. If we can remove it, and remove the need for another state in a ref, that would be even better.
• If we can't remove the branch, I would suggest we isolate the logic more to compute a const lastVisibleIndexChanged?: boolean independently.

[oliviertassinari]

I have added a console.log in development to monitor rerenders for scrolling this demo /components/data-grid/#commercial-version horizontally in 3 iterations:

HEAD

PR

It seems to fly. We can test the UX in production once Netlify has finished building.

[oliviertassinari]

https://deploy-preview-875--material-ui-x.netlify.app/components/data-grid/#commercial-version feels smoother than https://master--material-ui-x.netlify.app/components/data-grid/#commercial-version.

[DanailH]

Guys is there something else needed for this PR. I was thinking about how to test that corner case but couldn't come up with a good test case (only hiding and showing N columns won't cut it).

[oliviertassinari]

Yeah, this one is hard to test end-to-end. It's probably the kind of stuff to test with unit tests, like https://devexpress.github.io/devextreme-reactive/ are doing but I'm not sure it's worth it yet (it's a mess for refactoring). The logic of the fix is healthy: be less stateful, rely less on global refs.